People bathe using water from a broken water pipe along a street canal, after super typhoon Haiyan battered Tacloban City, in central Philippines November 13, 2013.

Reuters: Edgar Su

The United Nations has raised concerns that relief supplies are yet to reach some islands in the Philippines, more than a week after Typhoon Haiyan struck the nation.

The UN says it is facing a logistical nightmare to issue relief supplies with at least ten million people in need of basic necessities across several remote islands and communities in the central region.

Upon his visit to Ormox City and Basey town, President Benigno Aquino says millions of people in the central region require daily aid assistance.

"The challenge is, just for this region alone, 1.4 million people have to be fed everyday," Mr Aquino said.

The president says he won't leave the central region until he is confident relief efforts are running smoothly.

600,000 survivors yet to be reached

Etharin Cousin, the executive director of the United Nations World Food Program, says around 600,000 survivors of Typhoon Haiyan are yet to receive assistance from the agency, 11 days after the disaster struck.

Ms Cousin says the UN agency has so far delivered emergency supplies of rice and high-energy biscuits to 1.9 million people in the Philippines.

She says an initial assessment of areas ravaged by Super Typhoon Haiyan has estimated that 2.5 million survivors are in need of food.

"There are significant numbers of people still that we have yet to reach," Ms Cousin said.

"What we work to do is to reach those who don't have other means of accessing food and that number will continue to reduce as we move forward."

Ms Cousin says geographical challenges, including choked roads and accessing remote islands, is making it difficult to reach everyone affected.

"We are challenged but not overwhelmed and we will continue to perform the work necessary to meet the needs of the Philippine community," she said.

"The work goes on and we won't stop until everyone receives food assistance."